Nickel-Catalyzed Intermolecular Carbobromination of Alkynes

Organohalogen compounds such as alkenyl bromides are versatile and essential building blocks in organic synthesis. Herein, we describe the nickel-catalyzed intermolecular carbobrominations of alkynes with aryl bromides to form highly substituted and functionalized alkenyl bromides. The reductive elimination of the carbon–bromine bond from a Ni­(II) species, which is usually a disfavored process, is achieved from a high-valent Ni­(III) species in this reaction. This transformation not only expands the scope of transition-metal-complex-promoted bond-forming reactions but also, more particularly, accomplishes the formation of labile bonds, which is as challenging to achieve as the cleavage of inert bonds, such as C–O or C–H bonds.